1. Field
The present invention relates generally to video compression, and more particularly, to a method and apparatus for using Frame Rate Up Conversion (FRUC) techniques in scalable video coding.
2. Background
Rate adaptation in video and audio compression has typically been achieved through scalability (SNR, spatial, temporal) techniques, switching between bit streams coded at various bit-rates and multiple bit rate modes wherein the encoder delivers the content as a variety of media streams at variable bandwidths to the server. The server then delivers the appropriate stream based on the network conditions and/or the target audience.
Due to the limited bandwidth available in low bit-rate video application, some encoders apply the temporal sampling technique (also referred to as frame skipping) to meet the required compression ratios. Under this scenario, frames in the input sequence are periodically dropped from the encoding process and therefore not transmitted. Thus, instead of the whole input sequence, the decoder receives only partial information in the temporal direction. As a result, temporal artifacts such as motion jerkiness are introduced in the receiving side. Frame rate up conversion (FRUC) is used at the decoder to re-generate the skipped frames in order to reduce the temporal artifacts. Various techniques have been proposed for FRUC. Typically, motion compensated interpolation (MCI) technique provides the best solution in temporal FRUC applications. However, it is desirable to optimize the implementation of FRUC techniques on the decoder while minimizing the bit-rate of the video stream.